Yttrium aluminum garnet (having formula Y3Al5O12 and abbreviated as YAG) is a synthetic crystalline material of the garnet group, used as an artificial gem. YAG is commonly used as host material for solid-state lasers. Rare earth elements such as neodymium and erbium can be doped into YAG as active laser ions, the lasers being employed for a wide range of military applications, medical applications, and also as efficient tools for cutting and welding metals. Polycrystalline YAG is much cheaper to manufacture than its monocrystalline counterpart, and it was reported to have good mechanical properties [Mezeix L. and Green D.: Appl. Ceramic Technol. 3 (2006) 166-76]. Polycrystalline YAG becomes a promising substitute for single crystal YAG, and it might be used for a wide range of optical applications, if sufficient transparency is provided. The fabrication of transparent YAG ceramic by conventional pressure-less sintering approach was tried, but it requires relatively high sintering temperatures (above 1600° C.) and a subsequent HIP (High Isostatic Pressure) treatment, and is also accompanied by undesired grain growth [Fedyk R. et al.: Optical Materials 29 (2007) 1252-7]. The technique of spark plasma sintering (SPS) was attempted for the production of polycrystalline YAG, but only non-transparent specimens were obtained [Chaim R. et al.: Mater. Sci. Eng. A 429 (2006) 74-8]. It is therefore an object of the invention to provide a method of manufacturing transparent YAG.
It is another object of this invention to provide a method of manufacturing polycrystalline yttrium aluminium garnet (YAG) while employing spark plasma sintering (SPS).
It is a still further object of this invention to provide a method of manufacturing polycrystalline yttrium aluminum garnet (YAG) while employing relatively lower temperatures.
It is also an object of the invention to provide a cheap transparent YAG, with good hardness and strength.
Other objects and advantages of present invention will appear as description proceeds.